Apparatus for maintaining air temperature above the ground



W. L. KERLIN Oct. 19, 1954 APPARATUS FOR MAINTAINING AIR TEMPERATURE ABOVE THE GROUND Filed Aug. 16, 1949 I5 Sheets-Sheet l INVENTOR. lV/MMW z. fl

Oct. 19, 1954 w. KERLIN 2,691,347

APPARATUS FOR MAINTAINING AIR TEMPERATURE ABOVE THE GROUND Filed Aug. 16, 1949 3 Sheets-Sheet 2 BY I Oct. 19, 1954 w. KERLIN APPARATUS FOR MAINTAINING AIR TEMPERATURE ABOVE THE GROUND 3 Sheets-Sheet 3 Filed Aug. 16, 1949 INVENTOR. 404 z. kin/M Patented Oct. 19, 1954 UNITED STAT S ATENT OFFICE APPARATUS FOR MAINTAINING AIR TEM- PERATURE ABOVE THE GROUND 8 Claims.

This invention relates to an atmosphere conditioning device.

Generally it is the object of this invention to protect a predetermined area from frost or the like or to dry exposed products in open air, by providing a protective layer of heated air in such a manner as to confine the conduction and convection heat from the ground into a limited space.

Particular features of the invention which render this method and apparatus advantageous include: the directional discharge of streams of heated air at predetermined velocity and angle with respect to the ground so as to converge to the ground at the respective boundaries of the area to be protected; the utilization of heat of combustion for the expansion of comparatively large volume of air flow and the combination of the forces of combustion and expansion for creating said directional blasts or streams or jets of heated air; the selective arrangement of said jets of heated air to cover a selected area to a selected distance; the provision of a plurality of superimposed protective layers of jets directed at differing angles with respect to the ground, the layer closest to the ground being of the largest included angle with the ground so that while the outer layer keeps the pressure of the colder air from the ground, the lowest layer confines substantially closed circulating space for the convection and conduction heat from the ground and vegetation; the regulation of the pressure and velocity of said jets by raising the expansion point with respect to the jet outlets or by the shape of the outlet nozzles,

the former being a variable control to conform to variable atmospheric conditions, the latter being a predetermined condition conforming to the contour of the boundaries of the area to be protected; the emission of said jets of heated air at a suitable adjusted height above the height of the vegetation or objects on the ground; providing a combination of combustion means so as to insure the combustion pressure being higher than the pressure of air expansion, said combustion pressure and air expansion pressure combining to expel the heated air through suitable jet nozzles; a substantially closed system whereby the suction of the system creates a low pressure zone adjacent to the ground from which low pressure zone air is drawn for combustion and expansion and emission as jets which form a high pressure protective layer or umbrella for retainin the convection and conduction heats emanating from the ground and vegetation and transmitting a certain amount of I heat from the jet flow to the circulating air currents set up by the high pressure and low pressure directional flow by convection, the heat generated by this method and device being primarily converted into kinetic energy for the high pressure protective jets; the generation and the direction of the jets of heated air being so determined that the jet converges to the ground before its kinetic energy is exhausted; the utilization of the so-called stack energy in combustion in the production of the high pressure protective layer, and the utilization of substantially the entire heat and energy developed by fuel combustion and by air expansion.

I am aware that some changes may be made in the general arrangements and combinations of the several devices and parts, as well as in details of the construction thereof without departing from the scope of the present invention as set forth in the fOllOWiIlg specification, and as defined in the following claims; hence I do not limit my invention to the exact arrangements and combinations of the said device and parts as described in the said specification, nor do I confine myself to the exact details of the construction of the said parts as illustrated in the accompanying drawmgs.

With the foregoing and other objects in view, which will be made manifest in the following detailed description, reference is had to the accompanying drawings for the illustrative embodiment of the invention, wherein:

Fig. 1 is a diagrammatical view of application of my method and product.

Fig. 2 is a diagrammatic view of jet arrangement on an oblong area.

Fig. 3 is a diagrammatic view of jet arrangement on a square area.

Fig. 4 is a fragmental side view of my apparatus.

Fig. 5 is a top plan view of my apparatus.

Fig. 6 is a fragmental sectional view of my apparatus.

Fig. 7 is a fragmental sectional detail view of a modified outlet for my apparatus.

Fig. 8 is a top plan view of said outlet.

Fig. 9 is a perspective view of a nozzle for my apparatus.

Fig. 10 is a perspective View of another form of nozzle for my apparatus.

The invention is herein illustrated in a form adapted to the prevention of frost in orchards. The diagram in Fig. 1 represents approximate proportions for an installation covering about ten acres.

From a substantially central dispenser tower I, extended well above the vegetation on the ground 2, are emitted jets or streams of heated air at a considerable velocity directed to the respective boundaries of the land to be protected. Depending on local conditions, one or more sets of jets may be applied. In this illustration a so-called protective umbrella of heated air under comparatively high pressure is formed by three superimposed protective layers A, B and C, emitted from the to-weratdifiering angles. The top layer A is at about five degrees to the horizontal. The middle layer B is about eight degrees to the horizontal. The inner or bottom layer C is at about eleven degrees to the horizontal. This results in a substantial bulge or rise of the top layer A against the high pressure cold air thereabove and then, as the energy and heat of the layer Aiis gradually expended, the layer A curves to the ground at a remote point under said cold air pressure. The middle layer B, at its steeper included angle strikes the ground before its energy and heat are fully expended. The inner or bottom layer C strikes the ground at a still higher velocity than the other layers.

The protective layer C defines a space above the ground 2 within which is confined the convection and conduction heat emanating from the ground and vegetation. Thus an optimum temperature is maintained with some heat interchange between said layers and the circulating air currents set up by the high pressure and the low pressure zones and the eddy currents developed by the jets adjacent to the'tower stack by convection.

The protective layers are created by emitting a stream or streams of heated air at a comparatively high velocity, directed to the ground at a remote point from the source of the stream at the respective boundary of the ground to be protected. For instance, a series of jets may be used in overlapping relation to form a continuous umbrella. The individual jets of the series are adjusted to the respective boundary of their direction by the shaping of the jets and by the angles of the direction to regulate angle of incidence to the ground and velocity as well as lateral spread of each jet. An example is shown in Fig. 2 by an elongated strip of land, where opposite jets 3 spread lengthwise to each half of the land, and shorter but wider and steeper jets t cover the intermediate space to each half of the width of the land near the center and the source of the jets.

The heated air jets are created by multiple expansion. The primary expansion is that of combustion expansion in a fire box wherein the induced air caused by the burner system is expanded-and forced upward by pressure generated by a pressureblower and the force of combustion expansion. As sufficient volume of air to obtain proper velocities for the jets is not supplied by the burner system and pressure blower, additional air is supplied by volume blower, forcing air into a plenum chamber around said fire box and then through a series of properly sized tubes, with outlets opening into the tower stack, and joining with and being expanded by the rising expanded heated air current from fire box at the outlets of the tubes. The tubes are located on the walls of a frusto-conical chamber on the top of the burner chamber leading to a comparatively restricted outlet at about the tube outlets so that the increased velocity of the flower the products of combustion exerts a Venturi-like action for drawing additional air through the tubes. The resultant kinetic energy of the firebox combustion and the rapid air expansion at the tube outlets is then utilized to expel the expanded air through restricted nozzles, at the top of the tower stack, with high velocity into selected directions.

The combustion pressure below the tube outlets is maintained higher than the air expansion pressure at the tube outlets, to prevent back pressure below said tube outlets and also prevent back pressures in the tubes and in the 'lower plenum chamber. By adjusting the fuel supply and burn-' er heat the volume of combustion heat and pressures are raised or lowered and the pressure is increased or lowered to obtain jet velocities desired for-overcoming local conditions.

The suction to the center of the area protected, set up by the suction of the blowers and the eddy currents developed by the jets adjacent to tower stack draw the spent air of the protective layer near the ground toward the tower or the center, which results in a low pressure area near the ground, substantiallyforming a recirculatingsystem confined to the area to be protected.

A theory of operation, not fully proven, is that some radiant heat is *also trapped in the covered area because the heated air jets -containsome portion of the products of combustion such as carbon dioxide and water vapor, forming a black-body barrier to the escape of radiant heat.

The center tower stack l in an orchard, as

herein. illustrated, extends to suffi'cient height and the angle of the .jet tubes is such that the heat from the air jets will "be sufiiciently expanded by the time they reach the top of vegetation as not to damage said-vegetation and still have not entirely given up all their heat-before the selected boundary of the coverage desired has been reached. The source of the jets is at the top of the tower stack I.

The illustrative embodiment of my apparatus includes the dispensing tower stack I, with a dispensing plenum head 6 on its top, a heating or combustion device 1 at its "base, a plenum chamber 8 surrounding said combustion device 6-, and a series of converging properly sized'tubes 29 from said plenum chamber'fl and openinginto dispensing tower stack I, in a 'frusto-conicjal chamber [9.

The dispenser head'B includes a plenum cham her 9 from the walls of which radiate nozzles H at suitable angles downwardly so as to poin'tto the respective boundaries of the area to "be protected. The plenum chamber 9 receives the heated and expanded air under high pressure and the air rushes out through said nozzles in the form of high velocity jets. The velocity and direction of the jets is controlled by the nozzles l i. For instance the converging substantially conical nozzles i2 shown in Fig. 9 "provide a restricted round mouth for shaping the jet; and the elongated .mouth 13 of the nozzle shown in Fig. 10, spreads the jet into a fiat stream. In the form shown in Figs. 7 and 8, the outlet is formed by a collar flange i l inclined outwardly and downwardly and a conical plate [6 held by bars i l in spaced outwardly converging relation above said collar flange Ht, resulting in a ring like discharge mouth IS. The shape and angular arrangement of the nozzles 'll may be varied to suit local conditions.

In the herein illustration-in Fig. 6 is shown a dispenser head 6 with three generallysuperimposed rows 'of nozzles 1-9, 2! and 22. Each row isat a different included angle to the horizontal,

the lowest being of "the steepest angle and the top being the smallest angle to the horizontal.

For instance the top nozzle row i9 is at five degree, the middle nozzle row 2! is at eight degree, and the lowest nozzle row 22 is at eleven degree angles to the horizontal, emitting respectively the jets A, B and C heretofore described. The nozzles of each superimposed row are staggered with respect to the other rows, and the streams or jets overlap to form a complete curtain or umbrella over the area to be protected, converging to the boundaries of the land from the top of the tower I as an apex.

The heated air is impelled to the plenum chamber 9 through the stack of the tower l by the combined pressure of combustion and superheat expansion. The combustion device I on the base 23 of the tower l includes a combustion chamber 24 having a plurality of pressure burners 26 on opposite walls thereof. The walls of the chamber 24 are of suitable refractory material. A blower 27 suitably driven drives the air and the fuel under pressure into said combustion chamber.

The top chamber [9 of the combustion chamber 25 has formed therein a plurality of heating tubes 29 therein converging upwardly. The lower ends 3! of the heating tubes 29 open into said lower plenum chamber 8 around the exterior of the combustion chamber 24. A blower 33 of larger capacity than the first blower 2i, blows air into said lower plenum chamber 6 and through the heating tubes 29, out through the outlets 34 of said tubes 29. The outlets 34 are circumferentially spaced around the restricted discharge passage 35 of the top chamber H] of the combustion chamber 24. The air discharged from the tubes 29 into the combustion discharge passage 36 is again rapidly expanded by the heat of the products of combustion in the expansion chamber 3? and the heated air is forced by the combined force of combustion and expansion through the stack into the top plenum chamber 9 at the top and then out through the nozzles l l.

I claim:

1. In an apparatus for atmosphere conditioning, a dispensing tower, airflow dispensing devices on said tower spaced above the ground, and means to blow heated air out through said devices, said airflow dispensing devices including an outlet chamber, generally radial nozzles extended from said outlet chamber spaced circumferentially around the tower, the spacing between said nozzles being such that the airflow from adjacent nozzles forms overlapping air jets to form a substantially continuous layer of heated air above the ground.

2. In an apparatus for atmosphere conditioning, a dispensing tower, stationary airflow dispensing devices on said tower spaced above the ground, and means to blow heated air out through said devices, said dispensing devices including a plurality of generally radial directional nozzles spaced around the tower, the spacing between adjacent nozzles being such that airflow from adjacent nozzles form overlapping air jets.

3. In an apparatus for atmosphere conditioning, a dispensing tower, airflow dispensing devices on said tower spaced above the ground, and means to blow heated air out through said devices, said dispensing devices including air nozzles arranged in several layers being substantially radial to a common center and creating substantially overlapping air jets all around the tower to form a layer above the ground.

4. In an apparatus for atmosphere conditioning, a dispensing tower, airflow dispensing devices on said tower spaced above the ground, and means to blow heated air out through said devices, said last means including a burner for primary heating of airflow, means to produce a secondary forced airflow, tubes to conduct said secondary flow exteriorly to but exposed to the heat of the first flow, and a common conduit spaced above said burner for the heated and expanded air to said dispensing devices.

5. In an apparatus for atmosphere conditioning, a dispensing tower, airflow dispensing devices on said tower spaced above the ground, and means to blow heated air out through said devices, said dispensing devices including air nozzles arranged in several layers in overlapping generally radial positions relatively to said tower, and at angles converging downwardly and outwardly with respect to said tower.

6. In an apparatus for atmosphere conditioning, a combustion chamber, a stack for leading away the products of combustion, a secondary air conductor carrying outside air past the outside of said chamber to be heated and discharging said secondary air into said stack above said combustion chamber and in the path of said products of combustion for rapid expansion, and an outlet device on said stack for directing said expanded air under the combined force of combustion and expansion at predetermined angles and velocity with respect to the ground around said apparatus, said secondary air conductor including a plurality of upwardly converging air passages, and a converging heating chamber formed in said stack surrounding said passages.

7. In an apparatus for atmosphere conditioning, a combustion chamber, a stack for leading away the products of combustion, a secondary air conductor carrying outside air past the outside of said chamber to be preheated and discharging said secondary air into said stack in the path of said products of combustion for rapid expansion, an outlet chamber at the top of the stack, outlet nozzles extended from said outlet chamber to direct jets of heated air under the combined force of said combustion and expansion, said jets being generally radial and overlapping one another to form a covering over a predetermined area of ground.

8. In an apparatus for atmosphere conditioning, a dispensing tower, airflow dispensing devices on said tower spaced above the ground, and means to blow heated air out through said devices, said last means including a burner for primary heating of airflow, afrusto-conical upwardly converging top chamber above said burner, having a restricted outlet passage at its top, conductor elements within said frusto-conical top chamber conducting a secondary air flow from the outside to said restricted outlet, and a conduit connection between said restricted outlet and said dispensing devices.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,317,959 Cobb Oct. 7, 1919 1,357,314 Cobb Nov. 2, 1920 1,411,564 Cobb Apr. 4, 1922 1,629,921 Mansfield May 24, 1927 1,848,398 Towt Mar. 8, 1932 1,998,856 Towt Apr. 23, 1935 2,057,316 Rutherford Oct. 13, 1936 2,060,364 Chase Nov. 10, 1936 2,154,002 Kerrick Apr. 11, 1939 2,165,148 Nelson July 4, 1939 

